Circuit interrupter



April 13, 1944 "H, J. cRABBs 2,347,030

CIRCUIT INTERRUPTER Filed Jan. 15, 1941 3 Sheets-Sheet 1 April 18, '1944. H J, CRABBS 2,347,030

CIRCUIT INTERRUPTER Filed Jan. l5, 1941 3 Sheets-Sheet 2 fidaA Jig. 6.

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BY l 'Zi ATToNE April 18, 1944.. H. J. cRABBs CIRCUIT INTERRUPTER 3 Sheets-Sheet 5 Filed Jan. 15, 1941 WITNEssEs: 2Q/MLM. 6H. i'

` embodiments thereof when taken in vconnection withthe attached drawings,in'which: a

Patented Apr.- 18, 1944 Pennsylvania This invention relates generally to electric circuit interrupters, and more especially to disconnecting switches.

As the size and capacity of disconnecting switches have increased in recent years, the contact pressures necessary to provide good electrical contact between the relatively movable parts of these switches have also necessarily increased, and one objection has been that such high contact pressures have rendered the switches diiiicult to operate, since all relatively movable parts are frictionally engaged under the aforesaid high pressures.

It has, accordingly, been found desirable to provide for easier operation of disconnecting switches by limiting the area. of contactof the relatively movable parts of the switches, and by providing means for prying the switch blades loose in their opening movement. The instant invention is directed generally to improved con- `structions of disconnecting switches of this type,

and'one object of the invention is to provide al Contact of the switch shown m Fig. 1, and taken substantially on the line IV-IV of Fig. 1;

Fig. 5 is a fragmentary sectional view showing a preliminary step Vin the process of making the limited area contacts used in vthis invention;

Fig. 6 is a view similar to Fig. 5 but showing a. completed contact portion;

Fig. 7 is a cross sectional view taken through the'hinge contact of the disconnecting switch shown in Fig. 1; j

Fig. 8 is a side elevation view partially in section similar to Fig. 3 but showing a slightly modiiied arrangement of limited area contacts at the hinge end of a switch;

Fig. 9 is a partial elevation view of a modied form of operating means andbreak contact for a disconnecting switch;

Fig, 10 is a, partial cross sectional view of the switch shown in Fig. 9 and taken substantially on the line X-fX of Fig. 9;

' .Fg. 11 is a side elevational View of a disconnecting` switch similar to that shown in Fig. 1

- Another object of this invention is to provide a novel hinge contact construction for disconnecting switches.

Another object of this invention is to provide a disconnecting switch having limited area con-` tact portions which are adapted to be entirely provide a novel typefand method of forming a r limitedv area contact for circuit interrupters -such as. disconnecting switches. v These4 andother objects of this invention will become moreapparent upon consideration of the followingdetailed description 'of f preferred Figure 1 is a side elevational View of adiscon necting switch embodying the invention;

Fig, 2 is a sectional view of the switch vblade shown in Fig.' 1, taken substantially on the line n-II of Fig. 1;

Fig. 3 is an enlarged side elevational view partially in section of the hinge end cf the switch shown in Fig. 1, withone blade removed;

v Fig, vi is a partial sectional view of the break vbut showing a modifiedform of hinge tongue for the switch, and inustrating the switch in a partially open position;

Fig. 12 isa cross sectional view of the hinge i end 'of' the switch shown in Fig. 11 'taken substantially on the line XII-X11 of Fig. 11; and

Fig. 13 is a partial cross vsectional view taken substantiallyv on the line XIII-XIII of Fig. 11. Referring to the drawings, there is shown in Figs. 1 to 7 a disconnecting switch of the singlethrow type embodying the features of this invention. The switchv is adapted to be supported on a pair of insulators 2 and 4v, respectively, with the insulator 2 supporting the hinge contact tongue 6 of the switch, and insulator 4 adapted to support break contact tongue 8, with the contacts being .rigidly secured to the insulators in any desired manner such, for examplejas by bolts or th like. The'hinge contact tongue E is providedwitha laterally extending terminal portion I0, and break contact .tongue 8 is likewise provided with la laterallyextending terminal portion I2, for connection of line conductors to the switch. A split `switch'blade I4 is pivotally conlnected to the hinge contact 6 Vby a pivot bolt I8 passing through "the blade and hinge tongue. The blade I4, as stated, is of the split Vtype and includes the .pair of side blades I6 positioned at opposite sides of thehinge tongue. A pressure determining sleeve 20 is provided over pivot bolt I8 and betweenthe head of bolt I8 and nut 22. At'the outer sides ofthe switch blade Il'there' are provided coil compression springs 24v adapted to be compressed by nut 22 and thereby bias the blade sides I6 into engagement with the hinge contact tongue 6. It will be noted that sleeve acts to determine the maximum pressure which may be exerted on the blade sides, inasmuch as it is impossible to turn down nut 22 on the bolt more than the distance predetermined by the length of sleeve 20. Both the hinge contact tongue 6 and blade sides I6 are provided with projecting, limited area contact portions 26, which may be constructed in a manner to be hereinafter described.

The contact portions 26 are preferably arranged on opposite sides of the hinge tongue and may be substantially rectangular `in form as shown in Fig. 3, and extend substantially radially with respect to the blade pivot bolt I8. A spacing washer 28 is provided between each blade side I6 and hinge contact tongue 6. The spacing washers 28 are of less thickness than the distance between the blade sides I6 and hinge contact' tongue 6 when the raised contact portions 26 are in engagement. However, the washers 28 are of greater thickness than the projecting portion of each limited area contact 26, so that when the blade I4 is moved from the closed circuit position shown in Fig. 1 to an open circuit position wherein the limited area contact portions 26 on the blade and contact tongue are out of alignment, the blade sides I6 will be biased by coil springs 24 into engagement with spacing washers 28, while the limited area contact portions 26 will thereby be maintained out of engagement and will not be subjected to any frictional rubbing engagement during the major portion of the opening movement of the switch. In other words by the hinge contact construction illustrated, the contact portions of the blade and hinge contact tongue are engaged only adjacent the closed position of the switch and are entirely disengaged after a relatively minor portion of the movement of the switch blade in a direction to open the switch.

Break contact tongue 8 is provided with a slot 30 in its outer end, which slot is provided at its outer end with a divergent portion for receiving the connecting bolt 32, connecting blade sides I6 at this end of the switch. The bolt 32 is, like pivot bolt I8, provided with a pressure limiting sleeve 34 between the head of the bolt and nut 36 to limit the pressure which can be exerted on coil springs 38 positioned at the outer sides of the blade and engageable by the head of the bolt and nut 36. A spacing sleeve 40 is provided over sleeve 34 between blade sides I6, and is of a `length such that when the limited area contact .'portionsJof the blade and break tongue limited area contacts 42 are in engagement, the blade.

sides I6 are then apart a greater distance than the length of sleeve 48.

The sleeve 40 has the same function as spacing washers 28 at the hinge end of the switch in that it prevents contact of the blade contact portions 42 with the break contact tongue, and also prevents engagement of the break contact tongue limited area contact portions 42 with the switch blade when the contact portions 42 are moved out of engagement when the switch is opened. Obviously, when the switch is opened and moved from the position shown in Figs. 1 and 4, contact portions 42 will, upon a slight movement of the blade in a counterclockwise direction, be entirely disengaged, for example, as shown in Fig. ll, and at this point coil compression springs 38 move the blade sides I6 inwardly into engagement with spacing sleeve 48, thereby maintaining the contact portions 42 out of engagement, so that substantially no friction can be encountered at the break end of the switch upon continued movement of the blade to its open circuit position.

The break contact tongue 8 is provided with integral spaced supporting wall portions 44 (only one of which is shown) for supporting therebetween a latch lever 46 pivotally mounted on a pin 45 supported by walls 44. The latch lever includes an upper latching portion 48 adapted to hook over a latch pin 58 passing through blade sides I6, to lock the blade in its closed circuit position, wherein the cdntacting portions 42 and 26 thereof engage the corresponding contacting portions on the hinge and break contact tongues. The opposite end of latch lever 46 is provided with a toe 52 adapted to engage a portion of contact tongue 8 to limit movement of the latch lever in a clockwise direction about pivot pin 45. The latch lever is also provided with a shoulder 56 against which is seated a coil compression spring 54, which bears upon the contact tongue 8 to urge the latch lever in a clockwise direction about its pivot pin 45.

An operating lever 58 is pivotally mounted intermediate its ends between the sides I6 of switch blade I4, on a pivot bolt 68 passing through the blade. The outer end of this operating lever is provided with an aperture 62 for the reception of a hook stick or other operating member. The inner end of the operating lever is provided with a cam engaging portion 64 adapted to engage the curved cam surface 66 provided at the upper end of latch lever 46. Intermediate the inner end of operating lever 58 and its pivot bolt 68, there is provided an enlarged aperture 68 through which is passed a. headed pin 'I8 which extends freely through the aperture 68 and is closely tted in apertures in the blade sides I6. The upper edge of aperture 68 in operating lever 58 is tapered in form to provide opposed inclined surfaces 12 which are adapted to cooperate with the inward extending rounded heads of the cam rivets 14, provided on each blade side I6 as is more clearly shown in Fig. 2.

In operation, when it is desired to open the switch shown in Figs. 1 to '1, the operating lever 62 is moved in a counterclockwise direction. 'Ihis will cause the inner end 64 thereof to move latch lever 46 in a colmterclockwise direction to clear latch pin 5l until the latch lever 46 moves into engagement with break contact tongue 8. At the same time, the inclined surfaces I2 on the upper edge of aperture 68 in latch lever 58 will engage the enlarged heads of cam rivets 'I4 and force them, together with blade sides I6, laterally outwardly away from each other, and consequently move the limited contact portions 42 on the plate out of engagement with respect to the contact portions on break contact tongue 8. All this is accomplished without any substantial pivotal movement of the blade about pivot bolt I8 until, as stated before, latch lever 46 is moved into engagement with break contact'Y tongue 8, and at about the same time this occurs, the upper edge of aperture 68 will engage pin I8 connecting blade sides I6, thereby stopping pivotal movement of the operating lever about its pivot pin 60, whereupon a continued pull on operating lever 58 in the same direction will cause movement of switch blade I4 therewith about its pivot I8 away from break contact 28, to insert a relatively large air gap in. circuit. It can be aaimoso seen that before any attempt is made to pivotally move the blade in opening the switch, the sides of the blade are first moved laterally out of engagement with the hinge contact tongue by force multiplying means, that is, cam surfaces 12 and cam rivets 14, so that there will be substantially no friction opposing opening movement of the blade at the break end thereof.

Furthermore, after the contacting portions 42 at the break end of the switch have been moved laterally out of engagement with each other, a continued pull on operating lever 58 provides a pry-out action to start movement of the contacting portions 26 at the hinge end of the blade;

and since these contacting portions are also moved out of engagement with the contacting portions on the hinge tongue ina relatively minor portion of the path of opening movement of the switch blade, it is readily apparent that the major portion of the opening movement of the switch will be very easy, and will be substantially frictlonless. It should be noted that the pry-out action is not necessary to dlsengage the break contacts, but is useful mainly in overcoming friction between the contacts at the hinge end of the switch, and this is rendered substantially effortless because of the long lever arm available to move the hinge contacts. It will also be noted that there is no sliding friction necessary in opening the switch between the contact portions 42 on the switch blade and break contact tongue. At the hinge contact the only sliding friction encountered by the contacting portions 26 is merely that necessary to move these portions out of alignment with each other which, as will be readily apparent, is but a very minor portion of the movement of the switch in its circuit opening operation.

The l'mited area contactportions 26 and 42 heretofore described may be formed in a variety of diierent ways; as shown in Fig. 4, they may be mounted in slots out in the blade or contact tongue and secured therein in any desired manner such, for example, as by soldering, brazing or the like. Furthermore, these contact portions may have substantially at contacting surfaces if desired, but preferably the contact portions are of a shape and are constructed in a manner such as illustrated in Figs. and 6 of the drawings. This preferred form of limited area projecting contact construction is provided in the following manner.

As shown in Fig. 5, a layer of a noble metal 18, such as, for example, silver or the like, is preferably secured on the switch member 16, which may be a portion of the switch blade or contact tongue, in any desired manner such, for example, as by spraying or plating, or the like. After the strip 18 is secured to the switch member, the edges thereof are subjected to a pressing operation to press the edges into and below the surface of the contact member 16 as at 80, thereby effecting a cold iiow of the metal 18 towards the center thereof and away from its edge portions, to form a projecting central portion 8| which, as shown in Fig. 6, is preferably arcuate in form so as to form a substantial line contacting portion of a noble `metal which projects beyond the surface of the adjacent switch member. The method of forming a limited area pro- Jecting contact portion described above has the advantage that by subjecting the contacting material 18 to a pressing operation to effect a cold also at the same time this acts to harden the material 18 and improve the closeness of the grain thereof, to thereby provide a smooth hard and close grained contact portion, which is highly desirable in switches of this type.

In Fig. 8 there is illustrated a slightly modiiied form of hinge contact construction, and since most of the parts are like those previously described in connection with the embodiment of Figs. 1 to 7, like numerals will be used to designate these like parts. This embodiment of the invention differs from that previously described only in the shape of the limited area contact portions 82. As shown in Fig. 8, these are substantially circular in form and are spaced from each other and from the pivot bolt I8 of the switch. The contacting surface of the portions 82 may, like those previously described, be substantially flat or arcuate in form, preferably the latter, so that a plurality of point contacts are obtained between the switch blade and the hinge contact tongue, which, due to their different radial positions relative to the pivot bolt I8, are entirely disengaged upon a relatively minor portion of the opening movement of the switch blade, to thereby reduce the friction on these portions 82 in substantially the same manner in which the hinge contact portions 26 are disengaged in the embodiment previously described. In view of the similarity between these embodiments of the invention, the operation of the construction shown in Fig. 8 is believed to be obvious and, accordingly, will not be repeated.

In Figs. 9 and 10 there is shown a slightly` modied break contact and operating mechanism construction. Here also like numerals will be used to designate parts like those previously described. In this embodiment of the invention a break tongue 84 is employed having the upper end thereof cut olf at an angle, with a slot 86 opening at the upper end thereof for receiving bolt 32 provided on the switch blade, Limited area raised contact portions 88, similar to the portions 42 and 26 previously described, are provided on the blade and contact tongue, but, as shown, these portions 88 are provided on opposite sides of slot 86 and in substantial alignment, so as to lie at the same angle to the direction of movement of the blade adjacent the break contact tongue 84. It is believed obvious that the contact portions 88' will, like the portions 42, be engaged and disengaged by very slight movement of the switch blade at its fully closed position. The switch shown in Figs. 9 and 10 is adapted to operate by remotely controlled means having an operating rod 90 extending into a socket 92, of an operating member 64 adapted to be operatively associated with the switch blade. This operating member 84 is provided with an elongated aperture 96 for receiving a pin 98 similar to the pin 1|) previously described, and in this case the lower edge of the aperture 86 ,in member 94 is provided with opposed converging cam surfaces |02 adapted to cooperate when the switch is opened with the enlarged rounded heads of cam rivets |00.

The operation of the embodiment of this invention shown in Figs. 9 and l0 is very similar to that previously described, in that when it is desired to open this switch, the operating rod 99 is pulled outwardly, thereby causing the cam surfaces |02 to engage cam rivets |00 and move the sides |6 of the switch blade relatively outwardly so that the limited area contact portions 88 thereof move out of engagement with the corresponding portions on break contact tongue 84, whereupon the switch may be readily pivotally moved to its complete open circuit position. This operation is essentially the same as that previously described and is adapted for use especially with a remotely operated switch operating means.

. In Figs. 11 to 13, there are illustrated view s of a disconnecting switch much like that shown in Figs. 1 to 7 but embodying aslightly modified form of hinge contact construction. In this embodiment of the invention the hinge contact tongue |03 is of skeleton form and embodies a central thickened portion |08 through which pivot bolt i8 passes, and has contact supporting arms |04 extending substantially radially from pivot bolt I8, instead of the solid tongue construction shown in Fig. 1. The arms |08 of the hinge contact tongue shown particularly in Figs. 12 and 13 may have inserts |08 of silver or other noble metal substantially flush with the surface of the arms, while blade sides I8 have punched out portions H0, the projecting inner surface of which may be coated with silver H2, or some other noble metal preferably in the manner disclosed in connection with Figs. 5 and 6.

In Fig. 11,- the switch is illustrated in a partially open position, that is, the position in which the operating lever 58 has been operated to the point wherein it has laterally separated blade sides I6, released latch lever 4B from locking pin 50, and has pried the blade open to the position shown in Fig. 1l, where the latch lever is prevented from further rotative. movement in a counterclockwise direction about its pivot pin 60 by engagement of latch lever 4S with break contact tongue 8, and the upper edge of aperture 68 through the operating lever may also be in engagement with stop pin 10, so that continued movement of the operating lever 58 in the same direction will cause movement of the switch blade Il therewith about its` pivot |8 to a fully open position, wherein a large air gap is inserted in the circuit,

Referring again to Fig. 11, it will be noted that although in this figure the limited area contacts |08 and ||2 are not entirely disengaged, they have been slightly moved out of alignment by the prying-out action of actuating lever 58. and that upon further movement of the blade toward its fully open position, these limited area contacts |08 and H2 will be entirely disengaged in a relatively minor portion of this movement. It can be seen that as soon as the contact portions |08 and H2 are moved out of alignment, coil springs 38 will move the blades at the hinge end thereof together against the thickened portion |06 of the hinge tongue, and that the limited area contact portions ||2 on the blades will lie opposite the spaces between adjacent arms |04 of the hinge contact tongue.

From the foregoing, it is obvious that in this embodiment of the invention, as well as in those previously described, the only frictional rubbing contact of the limited area contacts at the hinge end of the switch is no more than that necessary to move the contacts a distance equal to the width thereof which obviously is a mere minor portion of the movement of the switch blade in a circuit opening or closing operation. During the remainder or major portion of the movement of the switch blade in a circuit opening or closing operation, the limited area contacts H2 on the blade, as stated above, will be-positioned opposite the spaces between contact tongue arms |04 and, therefore, out of engagement with any portion of the contact tongue, whereas the limited area vbe maintained in spaced relation with respect t0 the blade by engagement of the central portion of the hinge end of the blade with the thickened central portion |08 of the hinge contact tongue. Inasmuch as the operation of the switch actuating lever and the manner in which it relieves the pressure on the break contacts is identical with that previously described in connection with the embodiment of the inventionshown in Figs. 1 to 7, it will not be repeated here.

From the foregoing it is apparent that this inventlon provides a noval form of raised limited area contacts for a disconnecting switch or other circuit interrupting means, with a special arrangement of such contacts at the hinge end of a disconnecting switch to limit rubbingv of the contacts to a very small movement of the switch, and a special arrangement of operating mechanism in connection with limited contacts at the break end of the switch whereby substantially no frictional rubbing engagement takes place between the contacts at this end of the switch, thereby rendering the entire switch extremely easy of operation while providing high pressure limited area contact of the relatively movable parts of the switch in the closed circuit position.

Having described preferred embodiments of the invention in accordance with the patent statutes, it should be` understood that although preferred embodiments thereof have been described in detail, the invention should not be limited to these particular embodiments, inasmuch as it will be obvious to persons skilled in the art that many changes and modifications may be made in these particular embodiments without departing from the spirit and scope of this invention. Therefore, it is desired that the invention be interpreted as broadly as possible, and that it be limited only by the prior art and by what is specifically set forth in the following claims.

I claim as my invention:

1. In circuit interrupting means, a split switch blade mounted for movement into and out of engagement with a cooperating contact, an operating lever pivotally mounted on said blade and having an apertured portion, one edge of said lever aperture having opposed cam sides, and cam projections on said blade sides, respectively, and projecting into said aperture so as to he engageable by said cam sides upon movement of said lever in one direction to separate said blade sides, means carried by said blade and extending through said lever aperture for hunting movement of said lever relative to said blade, whereby continued movement of said lever causes movement of said blade therewith away from said cooperating contact to insert a relatively large gap in the circuit.

2. In a switch, spaced hinge and break contact members, a blade member pivotally mounted on said hinge contact member for movement into and out of engagement with said break contact member, the engaging portions of said blade and hinge contact member at the closed position of said switch comprising, limited area raised contacting portions on each of said blade and hinge members, said contacting portions being spaced about the pivot axis of said blade, and means hunting movement of said blade and hinge members toward each other at other switch positions to prevent said contacting portions of each member from engaging the other member except when said switch is substantially closed.

3. In a switch, spaced hinge and break contact contact portions |08 on the contact tongue will 75 members, a blade member pivotally mounted on said hinge contact member for movement into and out of engagement with said break contact member, the engaging -portions of said blade and hinge contact member at the closed position of said switch comprising, elongated limited area raised contacting portions on each of said bladel and hinge members,` said contacting portions being spaced about the pivot axis of said blade and extending substantially radially with respect to said axis, and means limiting movement of said blade and hinge member toward each other at other switch positions to prevent said contacting portions of each member from engaging said other member except when said switch is substantially closed. Y Y

4. I a switch, spaced hinge and break contact members, a blade member pivotally mounted on said hinge contact member for movement into and out of engagement with said break contact member, the engaging Portions of said blade and at least one of said contact members comprising at least one raised, limited area contacting portion on one of said members, said portion having an outer surface of a hardened noble metal with the outer edges thereof pressed to a thickness less than the central partthereof to a position below the surface of the member on which it is mounted. l

5. The method of making an electrical contact member with a projecting limited area contacting portion, including the steps of providing a layer of a noble metal on one surface of said member, and then pressing only edge portions of said metal into the material of said member to a position below the surface of said member in a manner to eiect a cold iow of said metal inwardly members, the engaging portions of said blade and hinged contact member comprising, limited area raised contacting portions on one of said members, with said contacting portions spaced about the pivot axis of said blade, the other of said members including limited area spaced contact arms extending radially from said pivot axis and positioned to engage said contact portions only substantially at the closed position of said switch.

9. The method of making an electrical contact member with a projecting limited area contacting portion, including the steps of providing a iiat layer of a noble metal on said member, and then pressing solely opposite edge portions of said metal toward said member to decrease'the thickness of said edge portions and thus provide a central limited area contact portion.

10, In a switch, spaced hinge and break contact members, a blade vmember pivotally mounted on said hinged contact member for movement into and out of engagement with said break contact member, the engaging portions of said blade and" pivot axis of said blade, and means limiting movefrom the edge portions thereof and outwardly with respect to said member.

6. The method of making an electrical contact member with a projecting limited area contacting portion, including the steps of adhering a layer of a noble metal on said member, and-then working said metal cold to eiect a iiow of said metal from edge portions thereof toward the center to provide a raised central portion and thin edge portions.

7. In a switch, spaced hinge and break contact members, a blade member pivotally mounted on said hinge contact member for movement into and out of engagement with said break contact member, the engaging portions of said blade and hinge contact member comprising, limited area raised contacting portions on both of said members, said contacting portions being spaced about the pivot axis of said blade and arranged to be engaged in the closed position of the switch, means biasing said blade and hinge contact member laterally into engagement to urge the contacting portions thereof into engagement under pressure, and

means limiting movement of said members to-v ment of said blade and hinge member toward each other at other switch positions to prevent said contacting portions of each member from engaging the other member except when said switch is substantially closed.

11. In circuit interrupting means, a split switch blade mounted for movement into and out of engagement with a cooperating contact, an operating lever pivotally mounted on said blade and having an apertured portion, one edge of said iever aperture having at least one cam side, and a cam projection on the blade side adjacent said cam side projecting into said aperture so as to be engageable by said cam side upon movement of said lever in one direction to separate said blade sides, means carried by said blade and extending through vsaid lever aperture for limiting movement of said lever relative to said blade, whereby continued movement of said lever causes movenient oi said blade therewith away from said cooperating contact to insert a relatively large gap in the circuit.

12. In a circuit interrupting means, a split switch blade mounted for movement into and out of engagement with a cooperating contact, an operating lever pivotally mounted on said blade between the sides thereof and having an aperture portion, one edge of said ieveraperture having opposed cam sides, cam projections on said blade sides, respectively, and projecting into said aperture so as to be engageable by said cam vsides upon movement of said lever in one direction to separate said blade sides, a pin connecting said blade sides and extending through said aperture for limiting movement of said lever relative to said blade, whereby continued movement of said lever causes movement of said blade therewith away from said cooperating contact to insert a relatively large gap in the circuit.

HERBERT J. CRABBS. 

